Method and device for D2D communication

ABSTRACT

An electronic device (10) including circuitry configured to perform communications with a road side unit, RSU, (50), a base station (30), and another electronic device (20) mounted to a moving object (22); receive, from the base station (30) or the RSU (50), parameters for performing intermittent device-to-device, D2D, communication with the another electronic device (20), the parameters including information indicating a resource pool used for performing the intermittent D2D communication with the another electronic device (20); and perform intermittent D2D communication with the another electronic device (10) based on the parameters received from the base station (30) or RSU (50).

CROSS REFERENCE TO RELATED APPLICATIONS

This application claims the benefit of Japanese Priority PatentApplication JP 2016-020142 filed Feb. 4, 2016, the entire contents ofwhich are incorporated herein by reference.

TECHNICAL FIELD

The present disclosure relates to a user terminal, a communicationdevice and a method.

BACKGROUND ART

By utilizing a communication device onboard a moving object such as avehicle, direct communication between the moving object and varioustarget objects is realized. Communication between a communication deviceonboard a moving object and various other communication devices iscalled vehicle-to-X (V2X) communication. For V2X communication,communication systems utilizing dedicated short range communications(DSRC) have been investigated thus far, but recently, investigation intocommunication systems utilizing mobile phone communication standardssuch as Long Term Evolution (LTE) is progressing. A system related tothe LTE communication standard is disclosed in NPL 1 below, for example.

CITATION LIST Non Patent Literature

-   NPL 1: 3GPP TR 22. 885 “Study on LTE support tor Vehicle to    Everything (V2X) services”

SUMMARY Technical Problem

In the V2X communication, a communication device carried by a pedestriancan contribute to secure safety of the pedestrian by performingcommunication with a communication device aboard a moving object, acommunication device installed on the side of a road or the like.However, the quantity of power of the communication device carried bythe pedestrian may be insufficient or the quantity of power that can beused for V2X communication may be limited, and thus it may be difficultto secure sufficient safety. Accordingly, it is desirable to provide aV2X communication scheme for reducing power consumption for acommunication device carried by a pedestrian.

Solution to Problem

According to an embodiment of the present disclosure, there is provideda user terminal including: a transceiver that performs communicationwith a moving object, a road side unit (RSU) or a base station; andcircuitry that sets parameters for intermittent communication with themoving object or the RSU.

According to another embodiment of the present disclosure, there isprovided an electronic device including: circuitry configured to performcommunications with a road side unit (RSU), a base station, and anotherelectronic device mounted to a moving object; receive, from the basestation or the RSU, parameters for performing intermittentdevice-to-device (D2D) communication with the another electronic device,the parameters including information indicating a resource pool used forperforming the intermittent D2D communication with the anotherelectronic device; and perform intermittent D2D communication with theanother electronic device based on the parameters received from the basestation or RSU.

According to another embodiment of the present disclosure, there isprovided a method including: performing communications with a road sideunit (RSU), a base station, and another electronic device mounted to amoving object; receiving, from the base station or the RSU, parametersfor performing intermittent device-to-device (D2D) communication withthe another electronic device, the parameters including informationindicating a resource pool used for performing the intermittent D2Dcommunication with the another electronic device; and performingintermittent D2D communication with the another electronic device basedon the parameters received from the base station or RSU.

According to another embodiment of the present disclosure, there isprovided an electronic device including: circuitry configured to performcommunications with a road side unit (RSU) and another electronic devicemounted to a moving object; receive, from the RSU, discontinuoustransmission (DTX) parameters and discontinuous reception (DRX)parameters for performing discontinuous vehicle-to-everything (V2X)communication with the another electronic device; and performdiscontinuous V2X communication with the another electronic device basedon the discontinuous transmission (DTX) parameters and the discontinuousreception (DRX) parameters received from the RSU.

Advantageous Effects of Invention

According to an embodiment of the present disclosure described above, aV2X communication scheme for reducing power consumption for acommunication device carried by a pedestrian is provided. Note that theeffects described above are not necessarily limited, and along with orinstead of the effects, any effect that is desired to be introduced inthe present specification or other effects that can be expected from thepresent specification may be exhibited.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 is an explanatory diagram for describing an overview of V2Xcommunication.

FIG. 2 is an explanatory diagram for describing a first scenario of V2Vcommunication.

FIG. 3 is an explanatory diagram for describing a second scenario of V2Vcommunication.

FIG. 4 is an explanatory diagram for describing a third scenario of V2Vcommunication.

FIG. 5 is an explanatory diagram for describing a fourth scenario of V2Vcommunication.

FIG. 6 is an explanatory diagram for describing a fifth scenario of V2Vcommunication.

FIG. 7 is an explanatory diagram illustrating a configuration of awireless communication system according to an embodiment of the presentdisclosure.

FIG. 8 is a block diagram illustrating an example of a logicalconfiguration of a UE according to the embodiment.

FIG. 9 is a block diagram illustrating an example of a logicalconfiguration of a UE according to the embodiment.

FIG. 10 is a block diagram illustrating an example of a logicalconfiguration of an eNB according to the embodiment.

FIG. 11 is a block diagram illustrating an example of a logicalconfiguration of an RSU according to the embodiment.

FIG. 12 is a diagram for describing technical features of a firstembodiment.

FIG. 13 is a diagram for describing technical features of theembodiment.

FIG. 14 is a diagram for describing technical features of theembodiment.

FIG. 15 is a diagram for describing technical features of theembodiment.

FIG. 16 is a diagram for describing technical features of theembodiment.

FIG. 17 is a diagram for describing technical features of theembodiment.

FIG. 18 is a diagram for describing technical features of theembodiment.

FIG. 19 is a diagram for describing technical features of theembodiment.

FIG. 20 is a diagram for describing technical features of theembodiment.

FIG. 21 is a diagram for describing technical features of a secondembodiment.

FIG. 22 is a diagram for describing technical features of theembodiment.

FIG. 23 is a diagram for describing technical features of theembodiment.

FIG. 24 is a diagram for describing technical features of theembodiment.

FIG. 25 is a diagram for describing technical features of theembodiment.

FIG. 26 is a diagram for describing technical features of theembodiment.

FIG. 27 is a diagram for describing technical features of theembodiment.

FIG. 28 is a block diagram illustrating a first example of a schematicconfiguration of an eNB.

FIG. 29 is a block diagram illustrating a second example of a schematicconfiguration of an eNB.

FIG. 30 is a block diagram illustrating an example of a schematicconfiguration of a smartphone.

FIG. 31 is a block diagram illustrating an example of a schematicconfiguration of a car navigation device.

DESCRIPTION OF EMBODIMENTS

Hereinafter, (a) preferred embodiment(s) of the present disclosure willbe described in detail with reference to the appended drawings. In thisspecification and the appended drawings, structural elements that havesubstantially the same function and structure are denoted with the samereference numerals, and repeated explanation of these structuralelements is omitted.

Also, in this specification and the appended drawings, multiplestructural elements having substantially the same function and structuremay in some cases be distinguished by different letters appended to thesame sign. For example, multiple elements having substantially the samefunction and structure or logical significance are distinguished as UEs10A, 10B, 10C, and so on as necessary. On the other hand, when notparticularly distinguishing each of multiple structural elements havingsubstantially the same function and structure, only the same sign willbe given. For example, when not particularly distinguishing UEs 10A,10B, 10C, each of the UEs 10A, 10B, 10C will be designated simply the UE10.

Hereinafter, a description will be given in the following order.

1. Introduction

1.1. V2X Communication

1.2. Technical Problem

2. Examples of Configuration

2.1. Examples of Configuration of System

2.2. Example of Configuration of UE (user terminal)

2.3. Example of Configuration of UE (moving object)

2.4. Example of Configuration of eNB

2.5. Example of Configuration of RSU

3. First Embodiment

4. Second Embodiment

5. Application Examples

6. Conclusion

«1. Introduction»

<1.1. V2X Communication>

By utilizing a communication device onboard a moving object such as avehicle, direct communication between the moving object and varioustarget objects is realized. Communication between a vehicle and varioustarget objects is called vehicle-to-X (V2X) communication. FIG. 1 is anexplanatory diagram for describing an overview of V2X communication. Asillustrated in FIG. 1, V2X communication may be vehicle-to-vehicle (V2V)communication, vehicle-to-infrastructure (V2I) communication,vehicle-to-pedestrian (V2P) communication, or vehicle-to-home (V2H)communication, for example. In addition, while not illustrated, V2Xcommunication also includes vehicle to nomadic device (V2N)communication, for example. Here, the first character and the thirdcharacter of V2V communication and the like respectively mean a startpoint and an end point and do not limit communication paths. Forexample, V2V communication is the concept including direct communicationbetween moving objects and indirect communication view a base station.

As illustrated in FIG. 1, the communication target of a vehicle in V2Vcommunication may be a passenger vehicle, a commercial or fleet vehicle,an emergency vehicle, or a transit vehicle, for example. Also, thecommunication target of a vehicle in V2I communication may be a cellularnetwork, a data centre, a fleet or freight management centre, a trafficmanagement centre, a weather service, a rail operation centre, a parkingsystem, or a toll system, for example. Also, the communication target ofa vehicle in V2P communication may be a cyclist, a pedestrian shelter,or a motorcycle, for example. Also, the communication target of avehicle in V2H communication may be a home network, a garage, orenterprise or dealer networks, for example.

Note that in V2X communication, communication systems utilizingdedicated short range communications (DSRC) have been investigated, butrecently, investigation into communication systems utilizing mobilephone communication standards such as Long Term Evolution (LTE) isprogressing.

Examples of applications of V2X communication include communicationsystems intended for forward collision warning, loss of control warning,emergency vehicle warning, emergency stop, adaptive cruise assist,traffic condition warning, traffic safety, automatic parking, routedeviation warning, message transmission, collision warning,communication range extension, traffic volume optimization, curve speedalert, pedestrian collision warning, or vulnerable person safety. Inaddition, V2X communication according to user equipment (UE) of a roadside unit (RSU) type, minimum QoS of V2X communication, V2X accessduring roaming, message provision through V2P communication for trafficsafety of pedestrians, mixed use for traffic management, improvement ofpositioning accuracy for traffic participants or the like areinvestigated.

A list of requirements for the above application examples is shown inthe following table 1.

TABLE 1 Minimum radio layer message Relative velocity receptionreliability Example of Absolute velocity between two Maximum(probability that cumulative Effective of UE supporting UEs supportingtolerable recipient gets it transmission range V2X service V2X servicelatency within 100 msec) reliability #1 Suburb 200 m 50 kmph 100 kmph100 ms 90% 99% #2 Main road 320 m 160 kmph 280 kmph 100 ms 80% 96% #3Freeway 320 m 280 kmph 280 kmph 100 ms 80% 96% #4 City 150 m 50 kmph 100kmph 100 ms 90% 99% #5 City 50 m 50 kmph 100 kmph 100 ms 95% —intersection #6 Campus/ 50 m 30 kmph 30 kmph 100 ms 90% 99% commercialdistrict

To meet the above requirements, standardization of the physical layer ofV2X is being investigated in 3GPP. A base technology of V2Xcommunication may be device-to-device (D2D) communication that wasstandardized in the past in 3GPP. Since D2D communication iscommunication between terminals without a base station, D2Dcommunication may be considered to aim for extension to V2Vcommunication, V2P communication or part of V2I communication. Such aninterface between terminals is called a PC5 interface. For V2Icommunication or V2N, extension of a previous technology ofcommunication between a base station and a terminal, such as LTE, isbeing considered. Such an interface between a base station and aterminal is called a Uu interface. In future investigation, it will benecessary to extend the PC5 interface and the Uu interface to meet theabove requirements. Main extension points may be, for example,improvement of resource allocation, Doppler frequency measures,establishment of a synchronization method, realization of low powerconsumption communication, realization of low delay communication and soon.

Various operation scenarios of V2X communication are considered. As anexample, examples of operation scenarios of V2V communication will bedescribed with reference to FIGS. 2 to 6.

FIG. 2 is an explanatory diagram for describing a first scenario of V2Vcommunication. In the first scenario, moving objects such as vehiclesdirectly perform V2V communication. A communication link in this casemay be called sidelink (SL).

FIG. 3 is an explanatory diagram for describing a second scenario of V2Vcommunication. In the second scenario, moving objects such as vehiclesindirectly perform V2V communication via evolved universal terrestrialradio access (E-UTRAN), that is, a base station. A communication linkfrom a transmitting side to the base station is called uplink (UL) and acommunication link from the base station to a receiving side is calleddownlink (DL).

FIG. 4 is an explanatory diagram for describing a third scenario of V2Vcommunication. In the third scenario, a moving object such as a vehicletransmits a signal to other moving objects sequentially through an RSUor a UE of RSU type and E-UTRAN. Communication links between the devicesare sequentially called SL, UL and DL.

FIG. 5 is an explanatory diagram for describing a fourth scenario of V2Vcommunication. In the fourth scenario, a moving object such as a vehicletransmits a signal to other moving objects sequentially through E-UTRANand an RSU or a UE of RSU type. Communication links between the devicesare sequentially called UL, DL and SL.

FIG. 6 is an explanatory diagram for describing a fifth scenario of V2Vcommunication. In the fifth scenario, moving objects such as vehiclesindirectly perform V2V communication through an RSU or a UE of RSU type.Communication links between the moving objects and the RSU or UE of RSUtype are SL.

The above-described scenarios become scenarios of V2P communication whenone of the moving objects is changed to a pedestrian. Similarly, thescenarios become scenarios of V2I communication or V2N communicationwhen one of the moving objects is changed to an infrastructure or anetwork, respectively.

<1.2. Technical Problem>

In V2P communication, communication is performed between a communicationdevice aboard a moving object and a communication device carried by apedestrian. An example of requirements in V2P communication will bedescribed below. As a relay requirement, delay within 500 ms from aserver to a terminal and within 100 ms for end-to-end is considered. Asan operation requirement, handling multiple mobile network operators(MNO) is considered. As a power consumption requirement, minimization ofbattery consumption is considered. As a coverage requirement, coverageof a range in which V2P communication can be performed 4 seconds orlonger before collision is considered. For example, in the case of 100km an hour, coverage having a diameter of approximately 110.8 m orlonger corresponding to 27.7 m/s×4 s is necessary. As a messagerequirement, typically 50 to 300 bytes, and a maximum of 1,200 bytes isconsidered. As a communication quality requirement, establishment ofcommunication in environments in which a relative speed of a motorcycleand a car is 280 km/h and a relative speed of a pedestrian and a car is160 km/h is considered.

A technical task of the present disclosure is minimization of batteryconsumption from among the aforementioned requirements. A smartphone orthe like considered as a communication device carried by a pedestrianhas insufficient battery capacity in many cases. Accordingly,minimization of battery consumption may be regarded as an important taskfor introduction of V2P communication.

«2. Examples of Configuration»

Hereinafter, examples of a configuration of a wireless communicationsystem that is common among embodiments will be described.

<2.1. Example of Configuration of System>

FIG. 7 is an explanatory diagram illustrating a configuration of awireless communication system according to an embodiment of the presentdisclosure. As illustrated in FIG. 7, the wireless communication systemaccording to the embodiment of the present disclosure includes a UE 10,a UE 20, a vehicle 22, an eNB 30, a GNSS satellite 40 and an RSU 50.

The eNB 30 is a cellular base station that provides a cellularcommunication service to the UE 20 positioned inside a cell. Forexample, the eNB 30 schedules resources for the UEs 10 and 20 tocommunicate by, and notifies the UEs 10 and 20 of the scheduledresources. Additionally, the eNB 30 conducts uplink communication ordownlink communication with the UEs 10 and 20 in the relevant resources.

The GNSS satellite 40 is an artificial satellite (communication device)that revolves around the earth in a predetermined orbit. The GNSSsatellite 40 transmits a global navigation satellite system (GNSS)signal including a navigation message. The navigation message includesvarious types of information for positioning, such as orbit informationand time information of the GNSS satellite 40.

The RSU 50 is a communication device installed on the side of a road.The RSU 50 may perform bi-directional communication with the vehicle 22,the UE 20 aboard the vehicle 22 or the UE 10 carried by a user 12. Whilethe RSU 50 may perform DSRC with the vehicle 22, the UE 20 aboard thevehicle 22 or the UE 10 carried by the user 12, the RSU 50 is assumed tocommunicate with the vehicle 22, the UE 20 aboard the vehicle 22 or theUE 10 carried by the user 12 through cellular communication system inthe present embodiment.

The UE 20 is a communication device that is mounted on the vehicle 22and moves along with traveling of the vehicle 22. The UE 20 has afunction of communicating with the eNB 30 according to control by theeNB 30. In addition, the UE 20 has functions of receiving the GNSSsignal transmitted from the GNSS satellite 40 and measuring locationinformation of the UE 20 from the navigation message included in theGNSS signal. Further, the UE 20 has a function of communicating with theRSU 50. Moreover, the UE 20 according to the present embodiment mayperform direct communication with the UE 10 carried by the user 12 orthe UE 20 aboard another vehicle 22, that is, D2D communication.Hereinafter, the UE 20 and the moving object 22 are collectively calledUE 20 if the UE 20 and the moving object 22 may not be distinguished.

The UE 10 is a communication device that is carried by the user 12 andmoves along with walking or running of the user 12 or movement of avehicle (a bus, a motorcycle, a car or the like) that the user 12 isriding. The UE 10 has a function of communicating with the eNB 30according to control by the eNB 30. In addition, the UE 10 has functionsof receiving the GNSS signal transmitted from the GNSS satellite 40 andmeasuring location information of the UE 10 from the navigation messageincluded in the GNSS signal. Further, the UE 10 has a function ofcommunicating with the RSU 50. Moreover, the UE 10 according to thepresent embodiment may perform direct communication with another UE 10or the UE 20, that is, D2D communication. Communication between the UE10 and the UE 20 is called V2P communication.

Note that although FIG. 7 illustrates the vehicle 22 as an example of amoving object, the moving object is not limited to the vehicle 22. Forexample, the moving object may also be an object such as a marinevessel, an aircraft, or a bicycle. In addition, although the abovedescribes the UE 20 as including the function of receiving the GNSSsignal, the vehicle 22 may have the function of receiving the GNSSsignal, and the vehicle 22 may output a GNSS signal reception result tothe UE 20.

<2.2. Example of Configuration of UE (user terminal)>

FIG. 8 is a block diagram illustrating an example of a logicalconfiguration of the UE 10 according to an embodiment of the presentdisclosure. As illustrated in FIG. 8, the UE 10 according to the presentembodiment includes an antenna part 110, a wireless communication unit120, a GNSS signal processing unit 130, a storage unit 140 and aprocessing unit 150.

The antenna part 110 radiates a signal output from the wirelesscommunication unit 120 as radio waves to the air. In addition, theantenna part 110 converts radio waves of the space into a signal andoutputs the signal to the wireless communication unit 120.

The wireless communication unit 120 transmits and receives signals. Forexample, the wireless communication unit 120 receives a downlink signalfrom the eNB 30 and transmits an uplink signal to the eNB 30.Furthermore, the wireless communication unit 120 transmits/receives asidelink signal to/from another UE 10, the UE 20 or the RSU 50.

The GNSS signal processing unit 130 is a component that processes theGNSS signal transmitted from the GNSS satellite 40. For example, theGNSS signal processing unit 130 measures location information and timeinformation of the UE 10 by processing the GNSS signal.

The storage unit 140 stores programs and various types of data foroperations of the UE 10 temporarily or permanently.

The processing unit 150 provides various functions of the UE 10. Forexample, the processing unit 150 controls communication performed by thewireless communication unit 120.

<2.3. Example of Configuration of UE (moving object)>

FIG. 9 is a block diagram illustrating an example of a logicalconfiguration of the UE 20 according to an embodiment of the presentdisclosure. As illustrated in FIG. 9, the UE 20 according to the presentembodiment includes an antenna part 210, a wireless communication unit220, a GNSS signal processing unit 230, a storage unit 240 and aprocessing unit 250.

The antenna part 210 radiates a signal output from the wirelesscommunication unit 220 as radio waves to the space. In addition, theantenna part 210 converts radio waves of the space into a signal andoutputs the signal to the wireless communication unit 220.

The wireless communication unit 220 transmits and receives signals. Forexample, the wireless communication unit 220 receives a downlink signalfrom the eNB 30 and transmits an uplink signal to the eNB 30.Furthermore, the wireless communication unit 220 transmits/receives aside link signal to/from the UE 10, another UE 20 or the RSU 50.

The GNSS signal processing unit 230 is a component that processes theGNSS signal transmitted from the GNSS satellite 40. For example, theGNSS signal processing unit 230 measures location information and timeinformation of the UE 20 by processing the GNSS signal.

The storage unit 240 stores programs and various types of data foroperations of the UE 20 temporarily or permanently.

The processing unit 250 provides various functions of the UE 20. Forexample, the processing unit 250 controls communication performed by thewireless communication unit 220.

<2.4. Example of Configuration of eNB>

FIG. 10 is a block diagram illustrating an example of a logicalconfiguration of the eNB 30 according to an embodiment of the presentdisclosure. As illustrated in FIG. 10, the eNB 30 according to thepresent embodiment includes an antenna part 310, a wirelesscommunication unit 320, a network communication unit 330, a storage unit340 and a processing unit 350.

The antenna part 310 radiates a signal output from the wirelesscommunication unit 320 as radio waves to the space. In addition, theantenna part 310 converts radio waves of the space into a signal andoutputs the signal to the wireless communication unit 320.

The wireless communication unit 320 transmits and receives signals. Forexample, the wireless communication unit 320 receives an uplink signalfrom the UE 10, the UE 20 or the RSU 50 and transmits a downlink signalto the UE 10, the UE 20 or the RSU 50.

The network communication unit 330 transmits and receives information.For example, the network communication unit 330 transmits information toother nodes and receives information from other nodes. For example, theother nodes include other base stations and a core network node.

The storage unit 340 stores programs and various types of data foroperations of the eNB 30 temporarily or permanently.

The processing unit 350 provides various functions of the eNB 30. Forexample, the processing unit 350 controls communication performed by theUE 10, the UE 20 and the RSU 50 subordinate thereto.

<2.5. Example of Configuration of RSU>

FIG. 11 is a block diagram illustrating an example of a logicalconfiguration of the RSU 50 according to an embodiment of the presentdisclosure. As illustrated in FIG. 11, the RSU 50 according to thepresent embodiment includes an antenna part 510, a wirelesscommunication unit 520, a storage unit 530 and a processing unit 540.

The antenna part 510 radiates a signal output from the wirelesscommunication unit 520 as radio waves to the space. In addition, theantenna part 510 converts radio waves of the space into a signal andoutputs the signal to the wireless communication unit 520.

The wireless communication unit 520 transmits and receives signals. Forexample, the wireless communication unit 520 receives a downlink signalfrom the eNB 30 and transmits an uplink signal to the eNB 30.Furthermore, the wireless communication unit 520 transmits/receives aside link signal to/from the UE 10, the UE 20 or another RSU 50.

The storage unit 530 stores programs and various types of data foroperations of the RSU 50 temporarily or permanently.

The processing unit 540 provides various functions of the RSU 50. Forexample, the processing unit 540 controls communication performed by thewireless communication unit 520.

Configuration examples which are common in embodiments have beendescribed.

Next, technical features of the respective embodiments will be describedin detail.

«3. First Embodiment»

The present embodiment reduces power consumption by activating ordeactivating the communication function of the UE 10 depending onposition.

The UE 10 activates or deactivates the communication function by thewireless communication unit 120 on the basis of information acquireddepending on position. For example, the UE 10 activates thecommunication function at a position at which a possibility of crashwith the moving object 22 is high (e.g., the vicinity of a road or thelike) and deactivates the communication function at a position at whichthe possibility is low (e.g., inside of a building). Accordingly, acommunication function activation period may be minimized and thus powerconsumption may be reduced.

Particularly, the activated or deactivated communication function is theV2P communication function in the present embodiment. Of course, the V2Pcommunication function corresponding to an activation or deactivationtarget includes the function of directly communicating with the UE 20using a sidelink and the function of performing indirect communicationusing a sidelink, uplink and downlink.

On the other hand, the UE 20, the eNB 30 or the RSU 50 notifies the UE10 of information for activating or deactivating V2P communication bythe UE 10. The information includes communication parameters,measurement parameters and the like which will be described below.

Activation is the concept including validation of all or a part of acommunication function, operation mode switching from a power-savingmode to a normal operation mode and so on. Deactivation is the conceptincluding invalidation of all or a part of a communication function,operation mode switching from the normal operation mode to thepower-saving mode and so on.

(1) Activation/Deactivation Depending on Location Information

Information acquired depending on position may be location informationof the UE 10. For example, the UE 10 measures the location information,determines necessity of activation or deactivation and controlsactivation or deactivation processing. Such steps may be performed bythe UE 10 or a device other than the UE 10. The device other than the UE10 includes any of the eNB 30 and the RSU 50, for example. Such devicesare collectively called a network device in contrast with the UE 10.

(1.1) Functions

(a) Measurement

A case in which the UE 10 measures the location information will bedescribed. For example, the UE 10 may measure the location informationthrough GNSS positioning or assisted GPS (A-GNSS) positioning. Inaddition, the UE 10 may measure the location information using D2D aidedpositioning technology that measures location through D2D communicationbetween terminals.

Next, a case in which the network device measures the locationinformation of the UE 10 will be described. For example, the eNB 30 maymeasure the location information using observed time difference ofarrival (OTDOA) technology, uplink time difference of arrival (UTDOA) orenhanced cell identification (E-CID) technology. Further, the RSU 50 mayestimate the location information using D2D aided positioningtechnology. In addition, the network device may estimate the locationinformation using terrestrial beacon systems (TBS) technology orpositioning technology using Wi-Fi (registered trademark) or Bluetooth(registered trademark).

The location information may include altitude information. The altitudeinformation may be measured by, for example, 3GPP indoor positioningtechnology.

(b) Determination

For example, the UE 10 previously acquires and stores map information.Then, the UE 10 determines whether to activate or deactivate V2Pcommunication on the basis of a result of comparison of the locationinformation thereof with the map information. For example, the UE 10determines activation of V2P communication at a position at which apossibility of crash with the moving object 22 is high (e.g., thevicinity of a road) and determines deactivation of V2P communication ata position at which the possibility is low (e.g., inside of a building).Further, the UE 10 may determine that V2P communication is activatedwhen the UE 10 is located within a predetermined distance from a road.

Additionally, the UE 10 may determine that V2P communication isactivated when the UE 10 is located within the range of a specific area.Here, the specific area is an intersection at which the RSU 50 is notinstalled, for example. Considering characteristics of V2Pcommunication, it is considered that V2P communication is not performedin an area in which there are many pedestrians, such as a scramblecrossing in a downtown area. In such an area, therefore, it isconsidered that the RSU 50 on which an image sensor is mounted isinstalled to determine a possibility of accident and notify theneighboring UE 10 or the like of the possibility of accident.Accordingly, it is desirable that V2P communication of the UE 10 bedeactivated in an area in which the RSU 50 is installed and V2Pcommunication be activated in an area in which the RSU 50 is notinstalled.

Although a case in which the UE 10 is the determination subject has beendescribed above, determination may be performed through the same methodeven when the determination subject is the network device.

(c) Control

The UE 10 controls activation processing or deactivation processing onthe basis of the determination result. In the case of activation, the UE10 acquires parameters related to V2P communication to be activated(referred to hereinafter as communication parameters). The UE 10 mayobtain the communication parameters from the network device orpreviously store the communication parameters.

Communication Parameters Common in Transmission/Reception

For example, the communication parameters may include band information,multiplexing information and so on used for communication. Themultiplexing information may include configuration information of timedivision duplex (TDD), for example. Further, the multiplexinginformation may include information for multiplexing of uplink anddownlink or information for multiplexing of the Uu interface and the PC5interface.

In addition, the communication parameters may include synchronizationrelated information. The synchronization related information may includeinformation that indicates frame timing or frequency information,acquired through the PC5 interface. Further, the synchronization relatedinformation may include timing offset information from universal timecoordinated (UTC). Here, offset means a frame timing difference betweenthe Uu interface and the PC interface.

Further, the communication parameters may include a GNSS functionactivation instruction.

Communication Parameters for Reception

For example, communication parameters may include information aboutresources monitored by the UE 10 for reception. Here, the resources mayrefer to both a control channel and a data channel. The informationabout resources may include information indicating a resource pool,information indicating a monitoring time window, information indicatinga time resource pattern and so on, for example.

Communication Parameters for Transmission

For example, the UE 10 may include information about resources used forthe UE 10 for transmission. Here, the resources may refer to both acontrol channel and a data channel. The information about resources mayinclude information indicating a resource pool, information indicating atime resource pattern, transmission power information, modulation andcoding scheme (MCS) information, information on the number ofretransmissions, and so on, for example.

Examples of communication parameters have been described. The UE 10activates V2P communication using the acquired communication parameters.

(1.2) Processing Flow

Variations of the aforementioned measurement, determination and controlprocessing flows will be described with reference to FIGS. 12 to 17.FIGS. 12 to 17 are sequence diagrams illustrating examples of activationprocessing flow depending on location information. The network device(eNB 30 or RSU 50) and the UE 10 are involved in each sequence.

First Case (UE->UE->UE)

This case is a case in which the UE 10 performs all of measurement,determination and control. In this case, signaling of the UE 10 andother devices is not necessary. This case is employed when the networkdevice is not present.

Second Case (UE->UE->Network Device)

This case is a case in which the UE 10 performs measurement anddetermination and the network device performs control. The sequence ofthis case is illustrated in FIG. 12. As illustrated in FIG. 12, first ofall, the UE 10 performs measurement (step S101) and determination (stepS102) and notifies the network device of information indicating thedetermination result (step S103). Subsequently, the network deviceperforms control (step S104) and notifies the UE 10 of activationnotification indicating activation and communication parameters (stepS105).

Third Case (UE->Network Device->UE)

This case is a case in which the UE 10 performs measurement and controland the network device performs determination. In this case, thecommunication function is autonomous communication such as Mode 2communication in D2D communication because the UE 10 performs control.The sequence of this case is illustrated in FIG. 13. As illustrated inFIG. 13, first of all, the UE 10 performs measurement (step S111) andnotifies the network device of measured location information (stepS112). Subsequently, the network device performs determination (stepS113) and notifies the UE 10 of activation notification (step S114).Then, the UE 10 performs control in response to the activationnotification (step S115).

Fourth Case (UE->Network Device->Network Device)

This case is a case in which the UE 10 performs measurement and thenetwork device performs determination and control. The sequence of thiscase is illustrated in FIG. 14. As illustrated in FIG. 14, first of all,the UE 10 performs measurement (step S121) and notifies the networkdevice of measured location information (step S122). Subsequently, thenetwork device performs determination (step S123) and control (stepS124) and notifies the UE 10 of activation notification andcommunication parameters (step S125).

Fifth Case (Network Device->UE->UE)

This case is a case in which the network device performs measurement andthe UE 10 performs determination and control. The sequence of this caseis illustrated in FIG. 15. As illustrated in FIG. 15, first of all, thenetwork device performs measurement (S131) and notifies the UE 10 ofmeasured location information (S132). Subsequently, the UE 10 performsdetermination (step S133) and control (step S134).

Sixth Case (Network Device->UE->Network Device)

This case is a case in which the network device performs measurement andcontrol and the UE 10 performs determination. The sequence of this caseis illustrated in FIG. 16. As illustrated in FIG. 16, first of all, thenetwork device performs measurement (step S141) and notifies the UE 10of measured location information (S142). Subsequently, the UE 10performs determination (step S143) and notifies the network device ofthe determination result (step S144). Then, the network device performscontrol in response to the determination result (step S145) and notifiesthe UE 10 of activation notification and communication parameters (stepS146).

Seventh Case (Network Device->Network Device->UE)

This case is a case in which the network device performs measurement anddetermination and the UE 10 performs control. In this case, thecommunication function is autonomous communication such as Mode 2communication in D2D communication because the UE 10 performs control.The sequence of this case is illustrated in FIG. 17. As illustrated inFIG. 17, first of all, the network device performs measurement (stepS151) and determination (step S152) and notifies the UE 10 of thedetermination result (step S153). Subsequently, the UE 10 performscontrol (step S154).

Eighth Case (Network Device->Network Device->Network Device)

This case is a case in which the network device performs measurement,determination and control. This case is a rare case.

(2) Activation Depending on Relative Relationship

The information acquired depending on position may be information thatindicates a relative relationship with another device (e.g., the UE 20,the RSU 50 or the like). For example, the UE 10 measures a signaltransmitted from the other device, determines to perform activation ordeactivation on the basis of a relative relationship with the otherdevice, which is indicated by the measurement result, and controlsactivation or deactivation processing. Such steps may be performed bythe UE 10 or a network device other than the UE 10. In the followingdescription, these steps are performed by the UE 10. The relativerelationship includes a relative speed relationship in addition to arelative location relationship.

(2.1) Functions

(a) Measurement

The UE 10 measures a signal transmitted from another device andestimates a relative relationship on the basis of the measurementresult. For example, a measurement target may be power of a V2Pcommunication band or power of a predetermined resource pool. Further,the measurement target may be a discovery signal. Moreover, themeasurement target may be a sidelink synchronization signal or asidelink broadcast signal. If the RSU 50 is of an eNB type, a downlinkcontrol signal transmitted from the RSU 50 may be the measurementtarget.

The UE 10 obtains parameters (referred to hereinafter as measurementparameters) for measuring the aforementioned measurement target asparameters for estimating the relative relationship. The UE 10 mayacquire the measurement parameters from a network device or previouslystore the measurement parameters. For example, the measurementparameters may include band information that indicates a band for whichmonitoring is performed. Further, the measurement parameters may includesynchronization information including frame timing, center frequencyinformation and the like in the band for which monitoring is performed.The synchronization information may be acquired from the GNSS signalfrom the GNSS satellite 40. In addition, the measurement parameters mayinclude measurement gap information including a measurement cycle, ameasurement duration, resource pool information of the measurementtarget and so on. The UE 10 acquires one or more of the aforementionedband information, synchronization information and measurement gapinformation depending on the measurement target.

The UE 10 measures the measurement target using the acquired measurementparameters. Accordingly, the UE 10 may decrease power consumption byappropriately restricting a measured frequency and timing. Here, the UE10 may change the measurement parameters depending on information of theUE 10. For example, the UE may change the measurement gap information,such as by increasing the measurement cycle and decreasing themeasurement duration if the UE 10 is separated from a road, depending onlocation information thereof. In addition, the UE 10 may change themeasurement parameters in response to the number of radio frequencies(RFs) (e.g., the number of RF circuits) or remaining battery capacity.According to such change, the UE may further decrease power consumptiondepending on a situation.

(b) Determination

The UE 10 determines whether to activate or deactivate V2P communicationon the basis of the aforementioned measurement result. For example, theUE 10 estimates the relative relationship with the other device andperforms determination on the basis of the estimated relativerelationship.

For example, the information indicating the relative relationship may beinformation that indicates whether the received power of the signaltransmitted from the UE 20 or the RSU 50 exceeds a threshold value. Forexample, the UE 10 may estimate the relative distance with the RSU 50 orthe UE 20 on the basis of a received signal strength indicator (RSSI),reference signal received power (RSRP) and reference signal receivedquality (RSRQ) of the band to determine whether activation ordeactivation of V2P communication is necessary.

For example, the information indicating the relative relationship may beinformation included in the signal transmitted from the UE 20 or the RSU50. For example, the UE 10 may recognize presence of the RSU 50 on thebasis of identification information (e.g., RSU ID) of a transmissionsource device included in a discovery signal or a broadcast signal todetermine whether activation or deactivation of V2P communication isnecessary. Further, the UE 10 may determine whether activation ordeactivation of V2P communication is necessary on the basis of flaginformation included in the discovery signal or the broadcast signalthat indicates whether V2P communication is necessary for the area.

The UE 10 may perform determination by appropriately combining theaforementioned information. In this case, the UE 10 may estimate therelative relationship in stages. For example, the UE 10 may decode thesignal to acquire information included in the signal only when thereceived power exceeds the threshold value.

Subsequently, an example of detailed determination standard will bedescribed.

For example, the UE 10 may activate V2P communication when it isestimated that the RSU 50 is present within a predetermined distance.According to this determination standard, accident occurrence in thevicinity of a road may be prevented using V2P communication.

On the other hand, the UE 10 may activate V2P communication when it isestimated that the RSI 50 is not present within the predetermineddistance. According to this determination standard, self-protection inan area in which the RSU 50 is not present nearby becomes possible. Assuch an area, an area where there are many pedestrians, such as ascramble crossing of a downtown area, as described above, anintersection at which the RSU 50 is not installed or the like isconsidered.

(c) Control

The UE 10 controls activation processing or deactivation processingdepending on the aforementioned determination result. In the case ofactivation, the UE 10 acquires communication parameters related to V2Pcommunication to be activated. The UE 10 may acquire the communicationparameters from a network device or previously store the communicationparameters. The content of the communication parameters has beendescribed above.

For example, when the communication parameters have been provided by thedecoded signal in the aforementioned measurement, the UE 10 may use thecommunication parameters or newly acquire communication parameters toupdate the communication parameters.

Further, the UE 10 may inquire the communication parameters of the eNB30 or the RSU 50. In case of the eNB 30, the inquiry may be a schedulingrequest.

In addition, the UE 10 may acquire the communication parameters from asignal broadcast from the eNB 30 or the RSU 50. For example, the eNB 30or the RSU 50 may include the communication parameters in a discoverysignal and transmit the discovery signal. Further, the RSU 50 mayperiodically regularly broadcast communication parameters which are usedlocally.

Here, the UE 10 may acquire the communication parameters in stages. Forexample, the UE 10 may previously initiate acquisition of thecommunication parameters at the stage of detecting weak power to preparefor activation of V2P communication. In addition, the UE 10 may acquirethe communication parameters only when received power exceeds thethreshold value.

The UE 10 activates V2P communication using the communication parametersacquired in this manner.

The UE 10 may acquire synchronization using the GNSS signal for V2Pcommunication to be activated when V2P communication is started. In thiscase, the UE 10 acquires synchronization related information to activatethe GNSS function.

The UE 10 may notify the eNB 30 or the RSU 50 that V2P communication hasbeen activated. Accordingly, the UE 10 may be included in target IDs ofdownlink multicast communication from the eNB 30.

(2.2) Processing Flow

The aforementioned measurement, determination and control processingflows will be described with reference to FIGS. 18 to 20.

FIG. 18 is a sequence diagram illustrating an activation processing flowdepending on a relative relationship. The UE 10, the vehicle 20 (i.e.,UE 20) and the eNB 30 or the RSU 50 are involved in this sequence. Asillustrated in FIG. 18, first of all, the eNB 30 or the RSU 50 notifiesthe UE 10 of measurement parameters (step S202). Subsequently, the UE 10measures a discovery signal, a synchronization signal or a broadcastsignal transmitted from the UE 20, the eNB 30 or the RSU 50 using themeasurement parameters (step S204). Then, the UE 10 performsdetermination on the basis of the measurement result (step S206) andnotifies the eNB 30 or the RSU 50 of the determination result (stepS208). The eNB 30 or the RSU 50 notified of the determination resultperforms control on the basis of the determination result (step S210)and notifies the UE 10 of communication parameters (step S212). Then,the UE 10 activates V2P communication using the communication parametersto start V2P communication (step S216).

FIGS. 19 and 20 are flowcharts illustrating examples of stepwisecommunication parameter acquisition processing flow. This flow isperformed by the UE 10.

As illustrated in FIG. 19, first of all, the UE 10 measures receivedpower of a signal from another device (step S302) and determines whetherthe received power is equal to or higher than a threshold value (stepS304). When it is determined that the received power is equal to orhigher than the threshold value (step S304/YES), the UE 10 previouslyacquires communication parameters (step S306) and ends the processing.On the other hand, when it is determined that the received power is notequal to or higher than the threshold value (step S304/NO), theprocessing is immediately ended.

As illustrated in FIG. 20, first of all, the UE 10 measures receivedpower of a signal from another device (step S402) and determines whetherthe received power is equal to or higher than a threshold value (stepS404). When it is determined that the received power is equal to orhigher than the threshold value (step S404/YES), the UE 10 acquires adecoding parameter for decoding the signal (step S406) and performsdecoding (step S408). For example, communication parameters are acquiredby decoding. Then, the UE 10 determines whether to activate V2Pcommunication (step S410). When it is determined that V2P communicationis activated (step S410/YES), the UE 10 controls activation processingof V2P communication to activate V2P communication (step S412) and endsthe processing. On the other hand, when it is determined that thereceived power of the signal from the other device is not equal to orhigher than the threshold value (step S404/NO) and it is determined thatV2P communication is not activated (step S410/NO), the processing isimmediately ended.

(3) Activation/Deactivation Depending on Getting in/Out of Moving Object

Information acquired depending on position may be information aboutgetting in/out of a moving object that transports the UE 10 (referred tohereinafter as transportation information). For example, when the UE 10detects that the user 12 gets into a moving object 22 such as a car, abus, a taxi or a streetcar, that is, the user 12 is transported by themoving object 22, the UE 10 may deactivate V2P communication. Further,when the UE 10 detects that the user 12 gets out of the moving object22, that is, the user 12 is not transported by the moving object 22, theUE 10 may activate V2P communication.

(a) Transportation Information Based on Wireless Communication

For example, information about whether the UE 10 is transported by themoving object, that is, transportation information, is acquired on thebasis of received power of a signal received from the UE 10 orinformation included in the received signal. Acquisition of thetransportation information may be performed by the UE 10 or a networkdevice such as the eNB 30 or the RSU 50.

In addition, the transportation information may be acquired through aprocedure of attaching to or detaching from a moving cell formed by theUE 20, for example. For example, when the attaching procedure isperformed by the UE 10, transportation information indicating that theUE 10 is transported by the moving object is obtained. When thedetaching procedure is performed by the UE 10, transportationinformation indicating that the UE 10 is not transported by the movingobject is acquired.

(b) Transportation Information Based on Short Range WirelessCommunication

For example, the transportation information may be acquired according tocommunication of the UE 10 with the moving object 22, more precisely, ashort range wireless communication terminal installed in the movingobject 22, that is, according to presence or absence of contact. Shortrange wireless communication schemes may include near fieldcommunication (NFC), Bluetooth, infrared data association (IrDA), ZigBee(registered trademark) and the like. Such a short range wirelesscommunication terminal may include a bus boarding fare adjustmentmachine, a keyless entry system of a private car, or the like.

(c) Transportation Information Based on Tracking of LocationInformation.

For example, the transportation information may be acquired on the basisof a tracking result of the location information of the UE 10. At thistime, whether the UE 10 is positioned on a road, a moving speed or thelike may be referred to.

«4. Second Embodiment»

The present embodiment further decreases power consumption bycontrolling reception timing or transmission timing in a state in whichthe communication function of the UE 10 has been activated.

Specifically, the UE 10 performs intermittent communication with the UE20 or the RSU 50. The transmitting side performs intermittenttransmission using a discontinuous transmission (DTX) scheme. On theother hand, the receiving side performs intermittent reception using adiscontinuous reception (DRX) scheme. Communication opportunities of theUE 10 decrease in both a case in which the UE 10 is the transmittingside and a case in which the UE 10 is the receiving side, and thus powerconsumption may be decreased.

Hereinafter, a case in which the UE 10 performs DRX as a receiving sidewill be described first and then a case in which the UE 10 performs DTXas a transmitting side will be described. In the following description,a target of intermittent communication of the UE 10 is the UE 20.

(1) DRX

Overview

FIG. 21 is an explanatory diagram for describing an example oftransmission and reception processing of typical V2P communication. Asillustrated in FIG. 21, moving objects (vehicle A and vehicle B)typically transmit default messages at periodic timings. A message forV2P communication is regarded as having a long transmission cycle (e.g.,approximately 1 Hz), compared to V2V communication. In V2Pcommunication, a base station that intensively controls finetransmission and reception timings is not present in many cases and thusautonomous distributed communication is performed. According to thiscircumstance, a pedestrian side (pedestrian A) constantly waits in areception standby state to receive messages transmitted from movingobject sides at respective timings of the moving object sides, asillustrated in FIG. 21.

In the present embodiment, the state of the receiving sideintermittently becomes a reception standby state using the DRX scheme.The reception standby state is a state in which a signal is received. Onthe other hand, a state in which a signal is not received is called areception sleep state. Of course, power consumption in the receptionsleep state is lower than that in the reception standby state. A periodin which the state of the receiving side intermittently becomes thereception standby state is called a DRX window hereinafter. Thetransmitting side transmits a message at the timing of the DRX window.

Specifically, the UE 10 performs intermittent communication (i.e.,reception) with the UE 20 using the DRX scheme. Accordingly, the UE 20performs communication (i.e., transmission) with the UE 10 according totiming at which intermittent communication of the UE 10 is possibleusing the DTX scheme. The UE 20 performs transmission at the timing atwhich the state of the UE 10 becomes the reception standby state andthus the reception standby state of the UE 10 may be shortened.Accordingly, power consumption of the UE 10 may be decreased.

(a) Parameter Setting

DRX Parameters

The UE 10 sets parameters (referred to hereinafter as DRX parameters)for performing intermittent reception using DRX.

For example, the DRX parameters may include a DRX cycle. For example, 1cycle is designated by combining the duration of the DRX window anddurations of other reception sleep states. Further, the DRX cycle mayinclude a start timing of 1 cycle (e.g., a frame number or the like).

The DRX parameters may include an on duration. The on duration isinformation that indicates the length of the DRX window. Similarly, theDRX parameters may include an off duration that indicates the length ofthe duration of a reception sleep state.

The DRX parameters may include a DRX extension. The DRX extension may bean extension from a default DRX window and may be set to ±α, forexample.

The DRX parameters may include a DRX resource pool. The DRX resourcepool is information about a resource pool used for DRX communication.

The DRX parameters may include a DRX frequency. The DRX frequency isinformation regarding a frequency used for DRX. Accordingly, a measuresuch as performing DRX only at a specific frequency may be possible inthe case of multicarrier V2P communication.

The DRX parameters may include a DRX group number. The DRX group numberis identification information of a group of one or more terminals thatperform DRX and identification information of a group to which the UE 10belongs. The UE 10 may identify the group thereof using the DRX groupnumber to use preset information corresponding thereto. The DRX groupnumber may be set on the basis of terminal information. For example, theDRX group number may be radio network temporary identifier (RNTI) mod X,international mobile subscriber identity (IMS) mod X or UE category.

The DRX parameter may include parameters for irregular DRX for an eventtrigger message or the like. Such parameters include a start framenumber, a start sub-frame number, an on duration and so on.

DRX Configuration

The UE 10 may acquire the DRX parameters from another device to set theDRX parameters. For example, the UE 10 may acquire DRX parametersprovided by a system information block (SIB) as system information fromthe eNB 30.

The DRX parameters may be set for each of types of transmitted andreceived messages. Message types include a periodical message, an eventtrigger message and so on. For the event trigger message, the onduration may be set to be short and periodicity may be increased. Inthis case, low delay is achieved.

The DRX parameters may be common among a plurality of UEs 10 or may bedifferent for each UE 10. For example, the DRX parameters may be set foreach group (i.e., DRX group) to which the UE 10 belongs. For example,congestion on specific resources is prevented from when different DRXparameters are set for each DRX group.

The DRX parameters may be set depending on the location information ofthe UE 10. For example, the DRX parameters may be set according towhether the UE 10 is positioned within the coverage of a specific eNB 30or RSU 50 or whether the UE 10 is positioned in a designated area. Whenthe UE 10 is positioned outside the coverage of the eNB 30, the UE 10may acquire the DRX parameters from previously stored preset informationand thus may not set the DRX parameters. Further, the DRX parameters maybe set depending on speed information of the UE 10.

Setting of Transmitting Side

The UE 20 transmits a message at least once in accordance with the DRXwindow of the receiving side. The transmission frequency of the UE 20may not be consistent with the reception frequency of the UE 10.Specifically, the reception frequency may be lower than the transmissionfrequency. For example, the UE 20 may transmit a periodical message at afrequency of 10 Hz and the UE 10 may receive the periodical message at afrequency of 1 Hz. The UE 20 sets transmission parameters such that amessage is transmitted within the DRX window of the UE 10 to maintain atleast a required message frequency.

(b) Control

The UE 20 transmits a message according to the reception timing (i.e.,DRX window) of the receiving side.

For such transmission timing control, three methods are considered. Thefirst one is a method through which the eNB 30 accurately decidestransmission resources. The second one is a method through which the eNB30 decides a resource pool and a transmitting side selects transmissionresources therefrom. The third one is a method through which thetransmitting side selects transmission resources from a previously setresource pool. The UE 20 transmits a message using transmissionresources specified by any of the aforementioned three methods.

As control methods for adjusting to the DRX window of the receivingside, addition of transmission timing, change of transmission timing anddivision of the number of repetitions are considered.

Addition of Transmission Timing

The UE 20 may add a transmission timing in response to the receptiontiming of the UE 10. For example, the UE 20 may additionally transmit amessage in response to the reception timing of the UE 10 whilemaintaining normal periodic message transmission. The messagetransmitted at the additional timing is called an additional messagehereinafter. The additional message may be retransmission of a defaultmessage. Detailed description will be given with reference to FIGS. 22and 23.

FIG. 22 is an explanatory diagram for describing an example oftransmission/reception processing of V2P communication, to whichtransmission timing is added. As illustrated in FIG. 22, a UE 20A(vehicle A) and a UE 20B (vehicle B) transmit default messages on thesame cycle (10 frames (100 ms)) at different timings. The DRX window ofthe UE 10 (pedestrian A) is set to a cycle of one to 100 frames (1 s).Accordingly, the UE 20A and the UE 20B transmit additional messages atthe timing of the DRX window of the UE 10.

FIG. 23 is an explanatory diagram for describing an example oftransmission/reception processing of V2P communication, to whichtransmission timing is added. As illustrated in FIG. 22, the UE 20A(vehicle A) and the UE 20B (vehicle B) transmit default messages on thesame cycle (10 frames (100 ms)) at different timings. The DRX window ofthe UE 10 (pedestrian A) is set to a cycle of one to 20 frames.Accordingly, the UE 20A and the UE 20B transmit additional messages atdifferent timings, at the timing of the DRX window of the UE 10.

The UE 20 may acquire transmission resource information for theaforementioned additional message from a network device such as the eNB30 or the RSU 50. The acquired transmission resource information may beaccurately decided transmission resource information or resource poolinformation with a wide choice. Either way, the UE 20 obtains timeresources and frequency resources for the additional message. Further,the UE 20 may acquire information about the DRX window of the UE 10.

The UE 20 may acquire the transmission resource information for theadditional message for itself. For example, the UE 20 may acquire thetransmission resource information for the additional message on thebasis of location information of the UE 10 or the UE 20. Further, the UE20 may use resources confirmed as being blank through carrier sensing astransmission resources for the additional message. In addition, the UE20 may acquire the transmission resource information for the additionalmessage from preset information.

The UE 20 transmits the additional message according to the transmissionresource information acquired in this manner. The transmission resourcesfor the additional message are called additional resources hereinafter.

For example, the UE 20 may repeatedly transmit the same message multipletimes in the additional resources. Further, the UE 20 may transmit theadditional message at a lower code rate than the default message. Inaddition, the UE 20 may transmit the additional message with highertransmission power than the default message. According to such control,an error rate at the receiving side may be improved.

Here, it is desirable that the UE 20 notify (e.g., the UE 10) ofinformation about the added transmission timing on sidelink. For thisreason, it is desirable to add a new parameter to an existing controlsignal (physical sidelink control channel (PSCCH)) transmitted onsidelink or to designate a new control signal. Parameters to bedesignated for such a control signal include information indicating thenumber of repetitions of transmission of the same message, informationon a redundancy version in repetitive transmission, MCS information andtransmission power information.

Change of Transmission Timing

The UE 20 may change existing transmission timing depending on thereception timing of the UE 10. For example, the UE 20 may change part oftimings of normal periodic message transmissions in response to thereception timing of the UE 10. A message transmitted at the changedtiming is referred to as a changed message hereinafter. Detaileddescription will be given with reference to FIGS. 24 and 25.

FIG. 24 is an explanatory diagram for describing an example oftransmission/reception processing of V2P communication, transmissiontiming of which is changed. As illustrated in FIG. 24, the UE 20A(vehicle A) and the UE 20B (vehicle B) transmit default messages on thesame cycle (10 frames (100 ms)) at different timings. The DRX window ofthe UE 10 (pedestrian A) is set to a cycle of one to 20 frames.Accordingly, the UE 20A and the UE 20B transmit changed messages byshifting parts of their default message transmission timings to beconsistent with the timing of the DRX window of the UE 10.

FIG. 25 is an explanatory diagram for describing an example oftransmission/reception processing of V2P communication, transmissiontiming of which is changed. As illustrated in FIG. 25, the UE 20A(vehicle A) and the UE 20B (vehicle B) transmit default messages on thesame cycle (10 frames (100 ms)) at different timings. DRX windows of aUE 10A (pedestrian A) and a UE 10B (pedestrian B) are set to a cycle ofone to 20 frames. Accordingly, the UE 20A and the UE 20B transmitchanged messages by shifting parts of their default message transmissiontimings to be consistent with the timing of the DRX window of the UE 10Aor UE B.

Here, it is desirable that the UE 20 notify (e.g., the UE 10) ofinformation about changed transmission timing on sidelink in order tochange the existing default message transmission timing. Accordingly,the control signal may be changed or newly designated, for example.Parameters to designate for such a control signal include a frame numberof a frame in which transmission timing is changed, an offset valueindicating a time-direction shift, an offset value indicating afrequency-direction shift, etc. The offset value indicating atime-direction shift may be an offset value based on the start point ofa frame or a sub-frame. The offset value indicating afrequency-direction shift may be an offset value based on the centerfrequency. In addition, the parameters to designate include informationindicating the number of repetitions of transmission of the samemessage, information on an RV in repetitive transmission, MCSinformation and transmission power information, for example.

Division of Number of Repetitions

The UE 20 may perform at least part of repetitive transmissions of thesame message, performed at the existing transmission timing, at atransmission timing added in response to the reception timing of the UE10. For example, the UE 20 decreases the number of repetitions oftransmission of the same default message, performed in a frame to whichDRX is allocated, and performs the reduced number of repetitivetransmissions at the added transmission timing. Typically, thetransmitting side repetitively transmits the same default messagemultiple times in V2X communication. The present control method is todivide the number of repetitions of transmission, to perform part ofrepetitive transmission at the existing transmission timing and to movea different part thereof to the added transmission timing.

Here, to change the number of repetitions of transmission of the samedefault message at the existing transmission timing, it is desirablethat the UE 20 notify (e.g., the UE 10) of information about change ofthe number of repetitions on sidelink. Accordingly, the control signalmay be changed or newly designated, for example. Parameters to bedesignated for such a control signal include an index of division of thenumber of repetitions, information about update of the number ofrepetitions, RV information and the like. The index of division of thenumber of repetitions is information indicating whether the number oftransmissions is divided. The information about update of the number ofrepetitions is information indicating the number of reduction ofrepetitive transmissions at the existing transmission timing. Further,it is desirable that the aforementioned information about the addedtransmission timing be included in the control signal.

(c) Processing Flow

FIG. 26 is a sequence diagram illustrating an example of a messagetransmission/reception processing flow using DRX. The UE 10, the vehicle20 (i.e., UE 20) and the eNB 30 or the RSU 50 are involved in thissequence. As illustrated in FIG. 26, first of all, the eNB 30 or the RSU50 transmits DRX parameters to the UE 10 (step S502). Subsequently, theUE 10 sets the state of the received DRX parameters to intermittentlybecome the reception standby state (step S504). The eNB 30 or the RSU 50transmits transmission resource information indicating transmissionresources depending on the DRX window to the UE 20 (step S506). Then,the UE 20 sets a transmission timing based on the transmission resourceinformation (step S508) and includes information about the settransmission timing in a control signal to notify, for example, the UE10 of the set transmission timing (step S510). The control signalincludes information about added or changed transmission timing orinformation about a change in the number of repetition of transmission.Subsequently, the UE 20 transmits a message at the timing in response tothe DRX window on the basis of the transmission resource information(step S512) and the UE 10 receives the message in the DRX window (stepS514).

(2) DTX

In the present embodiment, the state of the transmitting sideintermittently becomes a transmission state using the DTX scheme. Thetransmission state is a state in which a signal is transmitted. On theother hand, a state in which a signal is not transmitted is called atransmission stop state. Of course, power consumption in thetransmission stop state is lower than that in the transmission state. Aperiod in which the state of the transmitting side intermittentlybecomes the transmission state is called a DTX window hereinafter. Thereceiving side receives a message at the timing of the DTX window.

Specifically, the UE 10 performs intermittent communication (i.e.,transmission) with the UE 20 using the DTX scheme. Accordingly, the UE20 performs communication (i.e., reception) with the UE 10 in responseto the timing at which intermittent communication of the UE 10 becomespossible. The UE 20 may use the DRX scheme or may constantly wait in thereception standby state.

Here, considering that a transmitted message is, typically, a periodicalmessage which is periodically transmitted, it is desirable that the DTXwindow be periodically allocated. An event trigger message is anirregular case and thus is not assigned a DTX window and may betransmitted without particular restrictions.

(a) Parameter Setting

The UE 10 sets parameters for performing intermittent transmission usingDTX (referred to hereinafter as DTX parameters).

DTX Parameters

The DTX parameters may include a DTX cycle, for example. For example, 1cycle is designated by a combination of the duration of the DTX windowand the duration of another transmission stop state. Further, the DTXcycle may include a start timing (e.g., a frame number or the like) of 1cycle.

The DTX parameters may include an on duration. The on duration isinformation indicating the length of the DTX window. Similarly, the DTXparameters may include an off duration that indicates the length of theduration of the transmission stop state.

The DTX parameters may include a DTX extension. The DTX extension may bean extension from a default DTX window and may be set to ±α, forexample.

The DTX parameters may include a DTX resource pool. The DTX resourcepool is information about a resource pool used for DTX communication.

The DTX parameters may include a DTX frequency. The DTX frequency isinformation about a frequency used for DTX. According to this, a measuresuch as performing DTX only at a specific frequency may be performed inthe case of multicarrier V2P communication.

The DTX parameters may include a DTX group number. The DTX group numberis identification information of a group of one or more terminals thatperform DTX and identification information of a group to which the UE 10belongs. The UE 10 may identify the group thereof using the DTX groupnumber to use preset information corresponding thereto. The DTX numbermay be set on the basis of terminal information. For example, the DTXgroup number may be RNTI mod X, IMSI mod X or a UE category.

The DTX parameters may include parameters for irregular DTX for an eventtrigger message and the like. Such parameters include a start framenumber, a start sub-frame number, an on duration and so on.

DTX Configuration

The UE 10 may acquire the DTX parameter from other devices. For example,the UE 10 may obtain DTX parameters provided by an SIB as systeminformation from the eNB 30.

The DTX parameters may be set for each of types of transmitted andreceived messages. Message types include a periodical message, an eventtrigger message and so on. For the event trigger message, the onduration may be set to be short and periodicity may be increased. Inthis case, low delay is achieved.

The DTX parameters may be common among a plurality of UEs 10 or may bedifferent for each UE 10. For example, the DTX parameters may be set foreach group (i.e., DRX group) to which the UE 10 belongs. For example,congestion on specific resources is prevented when different DTXparameters are set for each DRX group.

The DTX parameters may be set depending on location information of theUE 10. For example, the DTX parameters may be set depending on whetherthe UE 10 is located within the coverage of a specific eNB 30 or RSU 50or whether the UE 10 is located in a designated area. When the UE 10 islocated within the coverage of the eNB 30, the UE 10 may acquire the DTXparameters from previously stored preset information and thus may notset the DTX parameters. Further, the DTX parameters may be set dependingon speed information of the UE 10. In addition, the DTX parameters maybe set depending on speed information of the UE 10. Further, the UE 10may use resources confirmed as being blank through carrier sensing astransmission resources for DTX.

Preset Information for DTX Parameters

The UE 10 may notify another device that controls the DTX parameters(e.g., UE 20, eNB 30 or RSU 50) of information for generating DTXparameters. Such information is referred to hereinafter as presetinformation.

For example, the preset information may include information of the UE 10for DTX group formation. Specifically, the preset information mayinclude a buffer status report (BSR) related to V2X communication.Further, the preset information may include a periodical BSR thatindicates buffer capacity of the periodical message. The presetinformation may include information unique to the UE 10, such as RNTI,IMSI or a UE category. In addition, the preset information may include aDTX extension request that requests a temporary increase in DTXopportunities (DTX window size, frequency or the like). Accordingly, itmay be possible to cope with a temporary message size increase.

The eNB 30 or the like may allocate the DTX parameters to each UE 10 onthe basis of such preset information.

(b) Processing Flow

FIG. 27 is a sequence diagram illustrating a messagetransmission/reception processing flow using DTX. The UE 10, the vehicle20 (i.e., UE 20) and the eNB 30 or the RSU 50 are involved in thissequence. As illustrated in FIG. 27, first of all, the UE 10 transmitspreset information for DTX parameters to the eNB 30 or the RSU 50 (stepS602). Subsequently, the eNB 30 or the RSU 50 that has received thepreset information generates the DTX parameters on the basis of thepreset information (step S604) and notifies the UE 10 of the generatedDTX parameters (step S606). Thereafter, the UE 10 sets the received DTXparameters (step S608) and intermittently transmits a message (stepS610). Then, the UE 20, the eNB 30 or the RSU 50 receives the message(step S612).

«5. Application Examples»

The technology of the present disclosure is applicable to variousproducts. For example, the eNB 30 may be realized as any type of evolvedNode B (eNB) such as a macro eNB, and a small eNB. A small eNB may be aneNB that covers a cell smaller than a macro cell, such as a pico eNB,micro eNB, or home (femto) eNB. Instead, the eNB may be realized as anyother types of base stations such as a NodeB and a base transceiverstation (BTS). The eNB may include a main body (that is also referred toas a base station device) configured to control wireless communication,and one or more remote radio heads (RRH) disposed in a different placefrom the main body. Additionally, various types of terminals to bediscussed later may also operate as the eNB by temporarily orsemi-permanently executing a base station function. Furthermore, atleast part of components of the eNB 30 may be realized in a base stationdevice or a module for the base station device.

For example, the UEs 10 and 20, or the RUS 50 may be realized as amobile terminal such as a smartphone, a tablet personal computer (PC), anotebook PC, a portable game terminal, a portable/dongle type mobilerouter, and a digital camera, or an in-vehicle terminal such as a carnavigation device. The UEs 10 and 20, or the RUS 50 may also be realizedas a terminal (that is also referred to as a machine type communication(MTC) terminal) that performs machine-to-machine (M2M) communication.Furthermore, the at least some of these structural elements of the UEs10 and 20, or the RUS 50 may be realized in a module (such as anintegrated circuit module including a single die) mounted on each of theterminals.

<5-1. Application Examples Regarding eNB>

(First Application Example)

FIG. 28 is a block diagram illustrating a first example of a schematicconfiguration of an eNB to which the technology of the presentdisclosure may be applied. An eNB 800 includes one or more antennas 810and a base station device 820. Each antenna 810 and the base stationdevice 820 may be connected to each other via an RF cable.

Each of the antennas 810 includes a single or multiple antenna elements(such as multiple antenna elements included in an MIMO antenna), and isused for the base station device 820 to transmit and receive radiosignals. The eNB 800 may include the multiple antennas 810, asillustrated in FIG. 28. For example, the multiple antennas 810 may becompatible with multiple frequency bands used by the eNB 800. AlthoughFIG. 28 illustrates the example in which the eNB 800 includes themultiple antennas 810, the eNB 800 may also include a single antenna810.

The base station device 820 includes a controller 821, a memory 822, anetwork interface 823, and a wireless communication interface 825.

The controller 821 may be, for example, a CPU or a DSP, and operatesvarious functions of a higher layer of the base station device 820. Forexample, the controller 821 generates a data packet from data in signalsprocessed by the wireless communication interface 825, and transfers thegenerated packet via the network interface 823. The controller 821 maybundle data from multiple base band processors to generate the bundledpacket, and transfer the generated bundled packet. The controller 821may have logical functions of performing control such as radio resourcecontrol, radio bearer control, mobility management, admission control,and scheduling. The control may be performed in corporation with an eNBor a core network node in the vicinity. The memory 822 includes RAM andROM, and stores a program that is executed by the controller 821, andvarious types of control data (such as a terminal list, transmissionpower data, and scheduling data).

The network interface 823 is a communication interface for connectingthe base station device 820 to a core network 824. The controller 821may communicate with a core network node or another eNB via the networkinterface 823. In that case, the eNB 800, and the core network node orthe other eNB may be connected to each other through a logical interface(such as an S1 interface and an X2 interface). The network interface 823may also be a wired communication interface or a wireless communicationinterface for radio backhaul. If the network interface 823 is a wirelesscommunication interface, the network interface 823 may use a higherfrequency band for wireless communication than a frequency band used bythe wireless communication interface 825.

The wireless communication interface 825 supports any cellularcommunication scheme such as Long Term Evolution (LTE) and LTE-Advanced,and provides wireless connection to a terminal positioned in a cell ofthe eNB 800 via the antenna 810. The wireless communication interface825 may typically include, for example, a baseband (BB) processor 826and an RF circuit 827. The BB processor 826 may perform, for example,encoding/decoding, modulating/demodulating, andmultiplexing/demultiplexing, and performs various types of signalprocessing of layers (such as L1, medium access control (MAC), radiolink control (RLC), and a packet data convergence protocol (PDCP)). TheBB processor 826 may have a part or all of the above-described logicalfunctions instead of the controller 821. The BB processor 826 may be amemory that stores a communication control program, or a module thatincludes a processor and a related circuit configured to execute theprogram. Updating the program may allow the functions of the BBprocessor 826 to be changed. The module may be a card or a blade that isinserted into a slot of the base station device 820. Alternatively, themodule may also be a chip that is mounted on the card or the blade.Meanwhile, the RF circuit 827 may include, for example, a mixer, afilter, and an amplifier, and transmits and receives radio signals viathe antenna 810.

The wireless communication interface 825 may include the multiple BBprocessors 826, as illustrated in FIG. 28. For example, the multiple BBprocessors 826 may be compatible with multiple frequency bands used bythe eNB 800. The wireless communication interface 825 may include themultiple RF circuits 827, as illustrated in FIG. 28. For example, themultiple RF circuits 827 may be compatible with multiple antennaelements. Although FIG. 28 illustrates the example in which the wirelesscommunication interface 825 includes the multiple BB processors 826 andthe multiple RF circuits 827, the wireless communication interface 825may also include a single BB processor 826 or a single RF circuit 827.

In the eNB 800 illustrated in FIG. 28, the processing unit 350 describedwith reference to FIG. 10 may be mounted in the wireless communicationinterface 825 (e.g., BB processor 826) or controller 821. Furthermore,the wireless communication unit 320 may be mounted in the wirelesscommunication interface 825 (e.g., RF circuit 827). The antenna part 310may be mounted in the antenna 810. The network communication unit 330may be mounted in the controller 821 and/or the network interface 823.In addition, the storage unit 340 may be mounted in the memory 822.

(Second Application Example)

FIG. 29 is a block diagram illustrating a second example of a schematicconfiguration of an eNB to which the technology of the presentdisclosure may be applied. An eNB 830 includes one or more antennas 840,a base station device 850, and an RRH 860. Each antenna 840 and the RRH860 may be connected to each other via an RF cable. The base stationdevice 850 and the RRH 860 may be connected to each other via a highspeed line such as an optical fiber cable.

Each of the antennas 840 includes a single or multiple antenna elements(such as multiple antenna elements included in an MIMO antenna), and isused for the RRH 860 to transmit and receive radio signals. The eNB 830may include the multiple antennas 840, as illustrated in FIG. 29. Forexample, the multiple antennas 840 may be compatible with multiplefrequency bands used by the eNB 830. Although FIG. 29 illustrates theexample in which the eNB 830 includes the multiple antennas 840, the eNB830 may also include a single antenna 840.

The base station device 850 includes a controller 851, a memory 852, anetwork interface 853, a wireless communication interface 855, and aconnection interface 857. The controller 851, the memory 852, and thenetwork interface 853 are the same as the controller 821, the memory822, and the network interface 823 described with reference to FIG. 28.

The wireless communication interface 855 supports any cellularcommunication scheme such as LTE and LTE-Advanced, and provides wirelesscommunication to a terminal positioned in a sector corresponding to theRRH 860 via the RRH 860 and the antenna 840. The wireless communicationinterface 855 may typically include, for example, a BB processor 856.The BB processor 856 is the same as the BB processor 826 described withreference to FIG. 28, except the BB processor 856 is connected to the RFcircuit 864 of the RRH 860 via the connection interface 857. Thewireless communication interface 855 may include the multiple BBprocessors 856, as illustrated in FIG. 29. For example, the multiple BBprocessors 856 may be compatible with multiple frequency bands used bythe eNB 830. Although FIG. 29 illustrates the example in which thewireless communication interface 855 includes the multiple BB processors856, the wireless communication interface 855 may also include a singleBB processor 856.

The connection interface 857 is an interface for connecting the basestation device 850 (wireless communication interface 855) to the RRH860. The connection interface 857 may also be a communication module forcommunication in the above-described high speed line that connects thebase station device 850 (wireless communication interface 855) to theRRH 860.

The RRH 860 includes a connection interface 861 and a wirelesscommunication interface 863.

The connection interface 861 is an interface for connecting the RRH 860(wireless communication interface 863) to the base station device 850.The connection interface 861 may also be a communication module forcommunication in the above-described high speed line.

The wireless communication interface 863 transmits and receives radiosignals via the antenna 840. The wireless communication interface 863may typically include, for example, the RF circuit 864. The RF circuit864 may include, for example, a mixer, a filter, and an amplifier, andtransmits and receives radio signals via the antenna 840. The wirelesscommunication interface 863 may include multiple RF circuits 864, asillustrated in FIG. 29. For example, the multiple RF circuits 864 maysupport multiple antenna elements. Although FIG. 29 illustrates theexample in which the wireless communication interface 863 includes themultiple RF circuits 864, the wireless communication interface 863 mayalso include a single RF circuit 864.

The eNB 830 illustrated in FIG. 29, the processing unit 350 describedwith reference to FIG. 10 may be mounted in the wireless communicationinterface 855, a wireless communication interface 863 and/or thecontroller 851. Furthermore, the wireless communication unit 320 may bemounted in the wireless communication interface 863 (e.g., RF circuit864). The antenna part 310 may be mounted in the antenna 840. Thenetwork communication unit 330 may be mounted in the controller 851and/or the network interface 853. In addition, the storage unit 340 maybe mounted in the memory 852.

<5-2. Application Examples Regarding UE and RSU>

(First Application Example)

FIG. 30 is a block diagram illustrating an example of a schematicconfiguration of a smartphone 900 to which the technology of the presentdisclosure may be applied. The smartphone 900 includes a processor 901,a memory 902, a storage 903, an external connection interface 904, acamera 906, a sensor 907, a microphone 908, an input device 909, adisplay device 910, a speaker 911, a wireless communication interface912, one or more antenna switches 915, one or more antennas 916, a bus917, a battery 918, and an auxiliary controller 919.

The processor 901 may be, for example, a CPU or a system on a chip(SoC), and controls functions of an application layer and another layerof the smartphone 900. The memory 902 includes RAM and ROM, and stores aprogram that is executed by the processor 901, and data. The storage 903may include a storage medium such as a semiconductor memory and a harddisk. The external connection interface 904 is an interface forconnecting an external device such as a memory card and a universalserial bus (USB) device to the smartphone 900.

The camera 906 includes an image sensor such as a charge coupled device(CCD) and a complementary metal oxide semiconductor (CMOS), andgenerates a captured image. The sensor 907 may include a group ofsensors such as a measurement sensor, a gyro sensor, a geomagneticsensor, and an acceleration sensor. The microphone 908 converts soundsthat are input to the smartphone 900 to audio signals. The input device909 includes, for example, a touch sensor configured to detect touchonto a screen of the display device 910, a keypad, a keyboard, a button,or a switch, and receives an operation or an information input from auser. The display device 910 includes a screen such as a liquid crystaldisplay (LCD) and an organic light-emitting diode (OLED) display, anddisplays an output image of the smartphone 900. The speaker 911 convertsaudio signals that are output from the smartphone 900 to sounds.

The wireless communication interface 912 supports any cellularcommunication scheme such as LTE and LTE-Advanced, and performs wirelesscommunication. The wireless communication interface 912 may typicallyinclude, for example, a BB processor 913 and an RF circuit 914. The BBprocessor 913 may perform, for example, encoding/decoding,modulating/demodulating, and multiplexing/demultiplexing, and performsvarious types of signal processing for wireless communication.Meanwhile, the RF circuit 914 may include, for example, a mixer, afilter, and an amplifier, and transmits and receives radio signals viathe antenna 916. The wireless communication interface 912 may also be aone chip module that has the BB processor 913 and the RF circuit 914integrated thereon. The wireless communication interface 912 may includethe multiple BB processors 913 and the multiple RF circuits 914, asillustrated in FIG. 30. Although FIG. 30 illustrates the example inwhich the wireless communication interface 912 includes the multiple BBprocessors 913 and the multiple RF circuits 914, the wirelesscommunication interface 912 may also include a single BB processor 913or a single RF circuit 914.

Furthermore, in addition to a cellular communication scheme, thewireless communication interface 912 may support another type ofwireless communication scheme such as a short-distance wirelesscommunication scheme, a near field communication scheme, and a radiolocal area network (LAN) scheme. In that case, the wirelesscommunication interface 912 may include the BB processor 913 and the RFcircuit 914 for each wireless communication scheme.

Each of the antenna switches 915 switches connection destinations of theantennas 916 among multiple circuits (such as circuits for differentwireless communication schemes) included in the wireless communicationinterface 912.

Each of the antennas 916 includes a single or multiple antenna elements(such as multiple antenna elements included in an MIMO antenna), and isused for the wireless communication interface 912 to transmit andreceive radio signals. The smartphone 900 may include the multipleantennas 916, as illustrated in FIG. 30. Although FIG. 30 illustratesthe example in which the smartphone 900 includes the multiple antennas916, the smartphone 900 may also include a single antenna 916.

Furthermore, the smartphone 900 may include the antenna 916 for eachwireless communication scheme. In that case, the antenna switches 915may be omitted from the configuration of the smartphone 900.

The bus 917 connects the processor 901, the memory 902, the storage 903,the external connection interface 904, the camera 906, the sensor 907,the microphone 908, the input device 909, the display device 910, thespeaker 911, the wireless communication interface 912, and the auxiliarycontroller 919 to each other. The battery 918 supplies power to blocksof the smartphone 900 illustrated in FIG. 30 via feeder lines, which arepartially shown as dashed lines in the figure. The auxiliary controller919 operates a minimum necessary function of the smartphone 900, forexample, in a sleep mode.

In the smartphone 900 illustrated in FIG. 30, the processing unit 150described with reference to FIG. 8, the processing unit 250 describedwith reference to FIG. 9 or the processing unit 540 described withreference to FIG. 11 may be mounted in the wireless communicationinterface 912 or the processor 901. Furthermore, the wirelesscommunication unit 120, the wireless communication unit 220 or thewireless communication unit 520 may be mounted in the wirelesscommunication interface 912 (e.g., RF circuit 914). The GNSS signalprocessing unit 130 or the GNSS signal processing unit 230 may bemounted in the sensor 907. The antenna part 110, the antenna part 210 orthe antenna part 510 may be mounted in the antenna 916. In addition, thestorage unit 140, the storage unit 240 or the storage unit 530 may bemounted in the memory 902.

(Second Application Example)

FIG. 31 is a block diagram illustrating an example of a schematicconfiguration of a car navigation device 920 to which the technology ofthe present disclosure may be applied. The car navigation device 920includes a processor 921, a memory 922, a global positioning system(GPS) module 924, a sensor 925, a data interface 926, a content player927, a storage medium interface 928, an input device 929, a displaydevice 930, a speaker 931, a wireless communication interface 933, oneor more antenna switches 936, one or more antennas 937, and a battery938.

The processor 921 may be, for example, a CPU or a SoC, and controls anavigation function and another function of the car navigation device920. The memory 922 includes RAM and ROM, and stores a program that isexecuted by the processor 921, and data.

The GPS module 924 uses GPS signals received from a GPS satellite tomeasure a position (such as latitude, longitude, and altitude) of thecar navigation device 920. The sensor 925 may include a group of sensorssuch as a gyro sensor, a geomagnetic sensor, and a barometric sensor.The data interface 926 is connected to, for example, an in-vehiclenetwork 941 via a terminal that is not shown, and acquires datagenerated by the vehicle, such as vehicle speed data.

The content player 927 reproduces content stored in a storage medium(such as a CD and a DVD) that is inserted into the storage mediuminterface 928. The input device 929 includes, for example, a touchsensor configured to detect touch onto a screen of the display device930, a button, or a switch, and receives an operation or an informationinput from a user. The display device 930 includes a screen such as aLCD or an OLED display, and displays an image of the navigation functionor content that is reproduced. The speaker 931 outputs sounds of thenavigation function or the content that is reproduced.

The wireless communication interface 933 supports any cellularcommunication scheme such as LET and LTE-Advanced, and performs wirelesscommunication. The wireless communication interface 933 may typicallyinclude, for example, a BB processor 934 and an RF circuit 935. The BBprocessor 934 may perform, for example, encoding/decoding,modulating/demodulating, and multiplexing/demultiplexing, and performsvarious types of signal processing for wireless communication.Meanwhile, the RF circuit 935 may include, for example, a mixer, afilter, and an amplifier, and transmits and receives radio signals viathe antenna 937. The wireless communication interface 933 may be a onechip module having the BB processor 934 and the RF circuit 935integrated thereon. The wireless communication interface 933 may includethe multiple BB processors 934 and the multiple RF circuits 935, asillustrated in FIG. 31. Although FIG. 31 illustrates the example inwhich the wireless communication interface 933 includes the multiple BBprocessors 934 and the multiple RF circuits 935, the wirelesscommunication interface 933 may also include a single BB processor 934or a single RF circuit 935.

Furthermore, in addition to a cellular communication scheme, thewireless communication interface 933 may support another type ofwireless communication scheme such as a short-distance wirelesscommunication scheme, a near field communication scheme, and a radio LANscheme. In that case, the wireless communication interface 933 mayinclude the BB processor 934 and the RF circuit 935 for each wirelesscommunication scheme.

Each of the antenna switches 936 switches connection destinations of theantennas 937 among multiple circuits (such as circuits for differentwireless communication schemes) included in the wireless communicationinterface 933.

Each of the antennas 937 includes a single or multiple antenna elements(such as multiple antenna elements included in an MIMO antenna), and isused for the wireless communication interface 933 to transmit andreceive radio signals. The car navigation device 920 may include themultiple antennas 937, as illustrated in FIG. 31. Although FIG. 31illustrates the example in which the car navigation device 920 includesthe multiple antennas 937, the car navigation device 920 may alsoinclude a single antenna 937.

Furthermore, the car navigation device 920 may include the antenna 937for each wireless communication scheme. In that case, the antennaswitches 936 may be omitted from the configuration of the car navigationdevice 920.

The battery 938 supplies power to blocks of the car navigation device920 illustrated in FIG. 31 via feeder lines that are partially shown asdashed lines in the figure. The battery 938 accumulates power suppliedform the vehicle.

In the car navigation device 920 illustrated in FIG. 31, the processingunit 150 described with reference to FIG. 8, the processing unit 250described with reference to FIG. 9 or the processing unit 540 describedwith reference to FIG. 11 may be mounted in the wireless communicationinterface 933 or the processor 921. Furthermore, the wirelesscommunication unit 120, the wireless communication unit 220 or thewireless communication unit 520 may be mounted in the wirelesscommunication interface 933 (e.g., RF circuit 935). The GNSS signalprocessing unit 130 or the GNSS signal processing unit 230 may bemounted in the GPS module 924. The antenna part 110, the antenna part210 or the antenna part 510 may be mounted in the antenna 937. Inaddition, the storage unit 140, the storage unit 240 or the storage unit530 may be mounted in the memory 922.

The technology of the present disclosure may also be realized as anin-vehicle system (or a vehicle) 940 including one or more blocks of thecar navigation device 920, the in-vehicle network 941, and a vehiclemodule 942. That is, the in-vehicle system (or a vehicle) 940 may beprovided as the device including the processing unit 250 described withreference to FIG. 9. The vehicle module 942 generates vehicle data suchas vehicle speed, engine speed, and trouble information, and outputs thegenerated data to the in-vehicle network 941.

«8. Conclusion»

An embodiment of the present disclosure has been described in detailwith reference to FIGS. 1 to 31.

According to the first embodiment, the UE 10 performs communication withthe moving object (i.e., UE 20), the RSU 50 or the eNB 30 and activatesor deactivates the communication function on the basis of informationacquired depending on position. Accordingly, a period in which thecommunication function is activated may be minimized and thus powerconsumption may be reduced.

According to the second embodiment, the UE 10 performs communicationwith the moving object (i.e., UE 20), the RSU 50 or the eNB 30 and setsparameters for intermittent communication with the UE 20 or the RSU 50.The UE 10 may further reduce power consumption in a state in which thecommunication function is activated by intermittently performingcommunication.

It should be understood by those skilled in the art that variousmodifications, combinations, sub-combinations and alterations may occurdepending on design requirements and other factors insofar as they arewithin the scope of the appended claims or the equivalents thereof.

Processes described using flowcharts and sequence diagrams in thespecification may not necessarily be performed in the illustratedorders. Some processing steps may be executed in parallel. Further,additional processing steps may be employed and some processing stepsmay be omitted.

In addition, a computer program for causing a processor (e.g., CPU, DSPor the like) included in a device (e.g., UE 10, UE 20, eNB 30 or RSU 50,or a module for such devices) of the specification to function as acomponent (e.g., processing unit 150, processing unit 250, processingunit 350, processing unit 540 or the like) of the device (in otherwords, a computer program for causing the processor to executeoperations of a component of the device) may also be generated. Further,a recording medium in which the computer program is recorded may beprovided. Moreover, a device including a memory that stores the computerprogram and one or more processors that can execute the computer program(e.g., a base station, a base station device or a module for the basestation device, or a terminal device or a module for the terminaldevice) may also be provided. In addition, a method including operationsof components of the device is included in the technology according tothe present disclosure.

Further, the effects described in this specification are merelyillustrative or exemplified effects, and are not limitative. That is,with or in the place of the above effects, the technology according tothe present disclosure may achieve other effects that are clear to thoseskilled in the art based on the description of this specification.

Additionally, the present technology may also be configured as below.

(1)

A user terminal including:

a communication unit that performs communication with a moving object, aroad side unit (RSU) or a base station; and

a processing unit that sets parameters for intermittent communicationwith the moving object or the RSU.

(2)

The user terminal according to (1), wherein the parameters includeinformation about a resource pool used for communication.

(3)

The user terminal according to (1) or (2), wherein the parametersinclude information about a frequency used for communication.

(4)

The user terminal according to any one of (1) to (3), wherein theparameters include identification information of a group to which theuser terminal belongs.

(5)

The user terminal according to any one of (1) to (4), wherein theparameters are set for each transmitted or received message type.

(6)

The user terminal according to any one of (1) to (5), wherein theparameters are set for each group to which the user terminal belongs.

(7)

The user terminal according to any one of (1) to (6), wherein theprocessing unit acquires the parameters from another device.

(8)

The user terminal according to (7), wherein the processing unit notifiesthe other device of information for generating the parameters.

(9)

The user terminal according to (8), wherein the information forgenerating the parameters includes a buffer status report.

(10)

The user terminal according to (8) or (9), wherein the information forgenerating the parameters includes information unique to the userterminal.

(11)

The user terminal according to any one of (1) to (10), whereinintermittent communication with the moving object or the RSU isintermittent transmission to the moving object or the RSU orintermittent reception from the moving object or the RSU.

(12)

A communication device configured to be mounted on a moving object,including a processing unit that performs communication with a userterminal according to a timing at which intermittent communication ofthe user terminal is possible.

(13)

The communication device according to (12), wherein the processing unitadds a transmission timing in response to a reception timing of the userterminal.

(14)

The communication device according to (13), wherein the processing unitnotifies the user terminal of information about the added transmissiontiming.

(15)

The communication device according to any one of (12) to (14), whereinthe processing unit changes an existing transmission timing in responseto a reception timing of the user terminal.

(16)

The communication device according to (15), wherein the processing unitnotifies the user terminal of information about the changed transmissiontiming.

(17)

The communication device according to any one of (12) to (16), whereinthe processing unit performs at least part of repetitive transmissionsof a same message, performed at an existing transmission timing, at atransmission timing added in response to a reception timing of the userterminal.

(18)

The communication device according to (17), wherein the processing unitnotifies the user terminal of information about change of the number ofrepetitions of transmission of the same message at the existingtransmission timing.

(19)

A method including:

performing communication with a moving object, an RSU or a base station;and setting parameters for intermittent communication with the movingobject or the RSU through a processor.

(20)

A method including

performing communication with a user terminal through a communicationdevice configured to be mounted on a moving object, according to atiming at which intermittent communication of the user terminal ispossible.

(21)

An electronic device including:

circuitry configured to

perform communications with a road side unit (RSU), a base station, andanother electronic device mounted to a moving object;

receive, from the base station or the RSU, parameters for performingintermittent device-to-device (D2D) communication with the anotherelectronic device, the parameters including information indicating aresource pool used for performing the intermittent D2D communicationwith the another electronic device; and perform intermittent D2Dcommunication with the another electronic device based on the parametersreceived from the base station or RSU.

(22)

The electronic device of (21), wherein the information indicating theresource pool for performing the intermittent D2D communication includesinformation identifying resources used for discontinuous transmission(DTX) and discontinuous reception (DRX).

(23)

The electronic device of any one of (21) to (22), wherein the parametersinclude information indicating a cycle of the intermittent D2Dcommunication and a start timing of the cycle.

(24)

The electronic device of (23), wherein the parameters include anextension parameter indicating an extension of the cycle.

(25)

The electronic device of any one of (21) to (24), wherein the parametersinclude identification information indicating a group of electronicdevices having common intermittent D2D communication parameters to whichthe electronic device belongs.

(26)

The electronic device of any one of (21) to (25), wherein the parametersare differently set for each of a plurality of types of transmitted orreceived messages.

(27)

The electronic device of any one of (21) to (26), wherein the parametersinclude information identifying a plurality of groups to which theelectronic device belongs, each group having different parameters forperforming intermittent D2D communication that are commonly applied toelectronic devices associated with each group.

(28)

The electronic device of any one of (21) to (27), wherein the circuitryis configured to acquire the parameters from the RSU.

(29)

The electronic device of any one of (21) to (28), wherein the circuitryis configured to transmit information for generating the parameters tothe base station or RSU.

(30)

The electronic device of (29), wherein the information for generatingthe parameters includes a buffer status report generated by theelectronic device.

(31)

The electronic device of any one of (29) to (30), wherein theinformation for generating the parameters includes information unique tothe electronic device.

(32)

The electronic device of any one of (21) to (31), wherein theintermittent D2D communication with the another electronic device isintermittent transmission to the another electronic device orintermittent reception from the another electronic device.

(33)

The electronic device of any one of (21) to (32), wherein the electronicdevice is configured to be mounted to another moving object, and thecircuitry is configured to perform the intermittent D2D communicationwith the another electronic device according to a timing at whichintermittent D2D communication of the another electronic device ispossible.

(34)

The electronic device of (33), wherein the circuitry is configured toadd a transmission timing based on a reception timing of the anotherelectronic device.

(15/35)

The electronic device of (34), wherein the circuitry is configured totransmit information indicating the added transmission timing to theanother electronic device.

(36)

The electronic device of any one of (33) to (35), wherein the circuitryis configured to change an existing transmission timing based on areception timing of the another electronic device.

(37)

The electronic device of (36), wherein the circuitry is configured totransmit information indicating the changed transmission timing to theanother electronic device.

(38)

The electronic device of any one of (33) to (37), wherein the circuitryis configured to perform repetitive transmissions of a same message at atransmission timing added based on a reception timing of the anotherelectronic device.

(39)

The electronic device of (38), wherein the circuitry is configured totransmit information indicating a change of a number of repetitions oftransmission of the same message at the existing transmission timing tothe another electronic device.

(40)

A method including:

performing communications with a road side unit (RSU), a base station,and another electronic device mounted to a moving object;

receiving, from the base station or the RSU, parameters for performingintermittent device-to-device (D2D) communication with the anotherelectronic device, the parameters including information indicating aresource pool used for performing the intermittent D2D communicationwith the another electronic device; and

performing intermittent D2D communication with the another electronicdevice based on the parameters received from the base station or RSU.

(41)

An electronic device including:

circuitry configured to

perform communications with a road side unit (RSU) and anotherelectronic device mounted to a moving object;

receive, from the RSU, discontinuous transmission (DTX) parameters anddiscontinuous reception (DRX) parameters for performing discontinuousvehicle-to-everything (V2X) communication with the another electronicdevice; and

perform discontinuous V2X communication with the another electronicdevice based on the discontinuous transmission (DTX) parameters and thediscontinuous reception (DRX) parameters received from the RSU.

REFERENCE SIGNS LIST

10 UE

12 user

20 UE

22 moving object

30 eNB

40 GNSS satellite

50 RSU

110 antenna part

120 wireless communication unit

130 GNSS signal processing unit

140 storage unit

150 processing unit

210 antenna part

220 wireless communication unit

230 GNSS signal processing unit

240 storage unit

250 processing unit

310 antenna part

320 wireless communication unit

330 network communication unit

340 storage unit

350 processing unit

510 antenna part

520 wireless communication unit

530 storage unit

540 processing unit

The invention claimed is:
 1. An electronic device comprising: circuitryconfigured to perform communications with a road side unit (RSU), a basestation, and another electronic device mounted to a moving object;receive, from the base station or the RSU, parameters for performingintermittent device-to-device (D2D) communication with the anotherelectronic device, the parameters including information indicating aresource pool used for performing the intermittent D2D communicationwith the another electronic device; and perform intermittent D2Dcommunication with the another electronic device based on the parametersreceived from the base station or RSU, wherein the parameters includeinformation identifying a plurality of groups to which the electronicdevice belongs, each group having different parameters for performingintermittent D2D communication that are commonly applied to electronicdevices associated with each group.
 2. The electronic device of claim 1,wherein the information indicating the resource pool for performing theintermittent D2D communication includes information identifyingresources used for discontinuous transmission (DTX) and discontinuousreception (DRX).
 3. The electronic device of claim 1, wherein theparameters include information indicating a cycle of the intermittentD2D communication and a start timing of the cycle.
 4. The electronicdevice of claim 3, wherein the parameters include an extension parameterindicating an extension of the cycle.
 5. The electronic device of claim1, wherein the parameters include identification information indicatinga group of electronic devices having common intermittent D2Dcommunication parameters to which the electronic device belongs.
 6. Theelectronic device of claim 1, wherein the parameters are differently setfor each of a plurality of types of transmitted or received messages. 7.The electronic device of claim 1, wherein the circuitry is configured toacquire the parameters from the RSU.
 8. The electronic device of claim1, wherein the circuitry is configured to transmit information forgenerating the parameters to the base station or RSU.
 9. The electronicdevice of claim 8, wherein the information for generating the parametersincludes a buffer status report generated by the electronic device. 10.The electronic device of claim 8, wherein the information for generatingthe parameters includes information unique to the electronic device. 11.The electronic device of claim 1, wherein the intermittent D2Dcommunication with the another electronic device is intermittenttransmission to the another electronic device or intermittent receptionfrom the another electronic device.
 12. The electronic device of claim1, wherein the electronic device is configured to be mounted to anothermoving object, and the circuitry is configured to perform theintermittent D2D communication with the another electronic deviceaccording to a timing at which intermittent D2D communication of theanother electronic device is possible.
 13. The electronic device ofclaim 12, wherein the circuitry is configured to add a transmissiontiming based on a reception timing of the another electronic device. 14.The electronic device of claim 13, wherein the circuitry is configuredto transmit information indicating the added transmission timing to theanother electronic device.
 15. The electronic device of claim 12,wherein the circuitry is configured to change an existing transmissiontiming based on a reception timing of the another electronic device. 16.The electronic device of claim 15, wherein the circuitry is configuredto transmit information indicating the changed transmission timing tothe another electronic device.
 17. The electronic device of claim 12,wherein the circuitry is configured to perform repetitive transmissionsof a same message at a transmission timing added based on a receptiontiming of the another electronic device.
 18. The electronic device ofclaim 17, wherein the circuitry is configured to transmit informationindicating a change of a number of repetitions of transmission of thesame message at the existing transmission timing to the anotherelectronic device.
 19. A method comprising: performing communicationswith a road side unit (RSU), a base station, and another electronicdevice mounted to a moving object; receiving, from the base station orthe RSU, parameters for performing intermittent device-to-device (D2D)communication with the another electronic device, the parametersincluding information indicating a resource pool used for performing theintermittent D2D communication with the another electronic device; andperforming intermittent D2D communication with the another electronicdevice based on the parameters received from the base station or RSU,wherein the parameters include information identifying a plurality ofgroups to which the electronic device belongs, each group havingdifferent parameters for performing intermittent D2D communication thatare commonly applied to electronic devices associated with each group.